Book of Abstracts (PDF) - International Mycological Association

IMC7 Main Congress Theme IV: POPULATION DYNAMICS AND ECOLOGY Posters
1039 - Molecular ecology of Bistorta vivipara
ectomycorrhiza in alpine tundra communities
J.H. Sønstebø * , K. Høiland & T. Schumacher
University of Oslo, Department of Biology, Division of
Botany and Plant Physiology, P.O. Box 1045 Blindern,
0316 Oslo, Norway. - E-mail: jornso@bio.uio.no
We have studied the diversity and phylogenetic affinities of
mycobionts of Bistorta vivipara ectomycorrhizas in four
alpine tundra plant communities in Norway, using ITS1-5.8
sequences as a diversity marker. ITS1-5.8 sequences
obtained by direct sequencing of 114 ectomycorrhizal root
tips compared with sequences from known fungal taxa
showed a high diversity of fungal mycobionts, including
mycobionts from a number of distantly related taxonomic
groups. The composition and taxonomic specificity of the
ectomycorrhizal fungi varied considerably among the study
sites. This suggests that B. vivipara is capable to interact
with a number of ectomycorrhizal fungal partners in its
many divergent habitats of the lowlands as well as in the
alpine zone. Frequent members of the B. vivipara
ectomycorrhizal symbiosis include Tomentella, Russula,
Inocybe, Cortinarius, Laccaria, Hebeloma, Cenococcum
and some unidentified members of Sebacinaceae. The
observed high abundance and diversity of Tomentella
mycobionts add to the earlier observations of importance of
this genus as ectomycorrhizal former also in boreal forest
ecosystems. The sebacinaceous ectomycorrhizal fungal
partners showed affinity (95% similarity) to orchid
mycorrhizal isolates from root tips of Neottia nidus-avis
retrieved from GenBank.
1040 - Analysing the genetic structure of Botrytis spp. in
lily and tulip fields using molecular markers
M. Staats * , P. van Baarlen & J.A.L. van Kan
Wageningen University, Laboratory of Phytopathology, PO
Box 8025, 6700 EE Wageningen, The Netherlands. - Email:
Martijn.Staats@fyto.dpw.wau.nl
Botrytis spp. that are pathogenic on flower bulb crops are
generally assumed to be host-specific. On lily, B. elliptica
produces primary necrotic lesions which potentially expand
into healthy tissue. On the non-host tulip, however, B.
elliptica can only cause primary necrotic lesions. The
reciprocal holds true for B. tulipae, which uses tulip as its
host. The mechanistic and genetic basis of host specificity
of the two Botrytis species mentioned is unclear.
Distinction between the species thus far relies on
morphological characteristics. At this moment it is
unknown to what extent sexual reproduction contributes to
genetic variation in local populations of Botrytis spp. in lily
and tulip fields. A sexual stage has so far been detected in
B. elliptica but not in B. tulipae. The purpose of this study
is to develop DNA markers to characterise the level of
inter- and intraspecific heterogeneity and the amount of
genetic recombination in B. elliptica and B. tulipae field
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Book of Abstracts
isolates. To reach these objectives we will use a
combination of sequence analysis and novel DNA
fingerprinting methods. - This research is funded by the
Dutch Technology Foundation STW.
1041 - Molecular markers associated with virulent and
avirulent phenotypes in populations of Uromyces
appendiculatus from bean fields in the Central USA
J.R. Steadman * , A.T. Alleyne, J.G. Fenton & K.M.
Eskridge
University of Nebraska, 406 Plant Sciences, Lincoln, NE
68583-0722, U.S.A. - E-mail: jsteadman1@unl.edu
Uromyces appendiculatus, cause of bean rust, is
characterized by highly diverse virulence phenotypes. The
use of race-specific rust resistance genes has been
complicated by the 'boom and bust' cycle. Pinto Olathe was
released as a rust resistant bean cultivar containing the Ur-
6 gene in 1979. The resistance only lasted 5 years.
Resistance gene pyramiding is a strategy to strengthen
race-specific resistance. Phenotyping the rust population is
time-consuming and costly. Pathogen variation can also be
monitored by genotyping. Previous work on molecular
variation in rust pathotypes have examined geographic
significance of rust races and the association between
resistance and virulence patterns. In the present study we
monitored the changing pattern of virulence on pinto
'Olathe' over the past 20 years using both molecular and
phenotypic markers. A population of over 130 isolates
from the Central USA representing both avirulent and
virulent pathotypes on pinto Olathe were analyzed using
molecular markers such as rep-PCR and RAPD-PCR.
These markers were found to discriminate between rust
pathogen genotypes with virulent or avirulent interactions
with the Ur-6 gene. In addition, cluster analysis of the
molecular data using UPGMA methods showed agreement
between statistical analysis and cluster associations of these
pathotypes with selected markers.
1042 - Annual production of leaf-decomposing fungi in
streams
K. Suberkropp 1* , B.R. Methvin 1 , M.D. Carter 2 & H.S.
Weyers 3
1 University of Alabama, Tuscaloosa, AL, U.S.A. - 2 Noth
Carolina State University, Raleigh, NC, U.S.A. - 3 U. S.
Geological Survey, Dover, DE, U.S.A. - E-mail:
ksuberkp@bama.ua.edu
We have determined the annual production of fungi
associated with decomposing leaves in seven streams in the
southeastern United States using rates of acetate
incorporation into ergosterol to calculate in situ growth
rates and ergosterol concentrations to estimate fungal
biomass. Annual fungal production ranged from 8-551
g/m 2 in these streams. Fungal production was significantly